Endemic and Native Species in Hawaii

Among Hawaii’s native land snails, about 99% are endemic, and the beetles are close behind. Those are some of the highest endemism rates recorded anywhere. Endemic means a species evolved here and lives nowhere else on earth, so you won’t find these snails in the wild outside Hawaii.

Endemic species live only in Hawaii. Native ones got here on their own but may live elsewhere too, so which of the two you count changes the number a lot. We pulled the figures from the Hawaii Biological Survey’s own published tables rather than taking the 90% headline at face value.

The quick answer is that the claim is partially true. More than 90% of Hawaii’s native species that live on land are endemic. Widen it to every native species, including the marine ones, and the share drops to just under half. Measured against all species recorded here, native and non-native together, it is about 39%.

Native (endemic and non-endemic) and alien species

Species in Hawaii’s diverse nature are either native, meaning they arrived without human help, or alien, meaning humans introduced them. Native species split further into endemic and non-endemic groups.

“Native” means that a species occurs naturally within a region, either because it evolved there or because it arrived without human assistance. For example, the Iʻiwi bird shown below is native (and endemic!) to the Hawaiian islands.

The Iʻiwi bird is endemic to Hawaii. Source: Iʻiwi|Puʻu oʻo Trail | 2013-12-17at12-43-209 by Bettina Arrigoni, licensed under CC BY 2.0

Native species can be split into endemic and non-endemic species. Endemic in biology means that a species is unique to a defined geographical location. Practically this means that a non-endemic native Hawaiian species has been found in ecosystems outside of Hawaii. Endemic species can only be found in Hawaii.

Finally, alien species are introduced from outside ecosystems. They can harm local species by competing for the same resources. Alien species are also called non-native or invasive species. In Hawaii, about 5,200 species are non-native, a fifth of everything recorded here (source).

How many species are there in Hawaii?

The Bishop Museum has been surveying the biodiversity in Hawaii since 1992 through the good work of the Hawaii Biological Survey.

Their most detailed assessment, published in 2003 (source), counted 25,615 species in the state: 9,987 endemic, 5,175 non-native, and about 10,450 native to Hawaii but living elsewhere too. A 2006 update raised the running total to 26,608 (source).

That 26,608 is still the figure Bishop Museum quotes, restated unchanged in its 2015 and 2020 reports. Nobody has recounted the state since. Writing in 2015, the Survey called Hawaii the only state in the country with an accurate accounting of every plant and animal within its borders, native and alien alike. The percentages below come from the 2003 breakdown, not from that 26,608 total.

The discrepancy comes from how the surveys group species. Species are often split into different groups based on taxonomy or living habitat. If you look only at the native species living on land (terrestrial species), you will recover the 90% number.  Marine species spread more easily (living on an island doesn’t stop them!), which lowers the number of endemic species.

The table breaks down Hawaii’s species counts by taxonomic group, per the 2003 Allison survey. The last row’s totals differ slightly from the 2014 Hawaii Biological Survey figures, since the table itself uses 2003 data.

Hawaii vs the Galapagos islands: comparing endemic species

None of those percentages change the bigger picture: Hawaii has far more endemic species than the Galapagos.

Take for example the Galapagos islands. These South American islands were made famous by Darwin’s work on evolution. Comparing the Galapagos with Hawaii shows far more endemic species on Hawaii:

Comparison of the endemic diversity of the Galapagos islands (left) with Hawaii (right). Adapted from Table 2 in Allen Allison 2003, Org. Divers. Evol. 3, 103–110 (2003), doi:10.1078/1439-6092-00065

Bishop Museum attributes the difference partly to distance. Hawaii sits 4,000 km from the nearest continental land mass; the Galapagos sit 1,000 km from South America. Four times the distance, measured the same way for both. Habitat variety adds to it: the Big Island alone spans 8 of the 13 Köppen climate sub-zones.

Resources used in this article

The writing of this article would not have been possible without the following resources:

• The Hawaii Biological Survey.
• The 2003 publication “Biological surveys – new perspectives in the Pacific” by Allen Allison (source).